Continuously chemically resistant spacer textile

ABSTRACT

The invention relates to a spacer textile ( 1 ) including a top textile ( 2 ), a bottom textile ( 3 ) and a spacer layer ( 5 ), wherein the top textile ( 2 ) and the bottom textile ( 3 ) are connected together by the spacer layer ( 5 ). The top textile ( 2 ), the bottom textile ( 3 ) and the spacer layer ( 5 ) are monofilament fibers from inert fluorocarbons. The invention relates additionally to the use of the spacer textile ( 1 ) according to the invention as at least in part sheathing of an electrode ( 13, 14 ) in an electroplating bath ( 11 ), as a lining of operating, bearing and/or transport surfaces ( 31 ), or as filter or support material in chemically aggressive media.

The invention relates to a spacer textile.

Spacer textiles are known in the prior art. They include a top textile and a bottom textile which are connected together by means of a spacer layer, the spacer layer in this case providing a three-dimensional structure of the spacer textile. Depending on the development of the spacer layer, spacer textiles can obtain different properties, for example with regard to flexibility and damping action. The top textile, the bottom textile and the spacer layer are all formed from fibers.

It is the object of the present invention to create a continuously chemically resistant spacer textile.

This object is achieved by a spacer textile according to the main claim. Advantageous uses of the spacer textile according to the invention are the object of the sub-claims. Advantageous further developments of the spacer textile and the uses thereof are the object of the dependent claims.

Accordingly, the invention relates to a spacer textile including a top textile, a bottom textile and a spacer layer, wherein the top textile and the bottom textile are connected together by the spacer layer in such a manner that they are at a spacing from each other, wherein the top textile, bottom textile and spacer layer are formed by fibers, and wherein the fibers are monofilaments of inert fluorocarbons.

The invention also relates to the use of a spacer textile according to the invention for the at least in part sheathing of an electrode in an electroplating bath, the spacer textile being permeable in such a manner that it does not impair electrolytic processes.

The invention additionally relates to the use of a spacer textile according to the invention as a lining of operating, bearing and/or transport surfaces.

The invention additionally relates to the use of a spacer textile according to the invention as filter or support material in chemically aggressive media.

First of all some terms used in conjunction with the invention are explained:

The term “spacer textile” refers to a three-dimensional textile material of individual fibers including a top and a bottom textile which are at a spacing from each other but are connected together by a spacer layer. Spacer textiles in terms of this invention can be, in particular, spacer knitted fabrics, spacer crocheted fabrics and the like.

A “monofilament” is a fiber which includes just one single long molecular chain. Monofilaments according to the invention can be produced, for example, by extruding fluorocarbons.

Such materials and substances are called “inert” when they do not react or only react in a very, very small way to potential reaction partners.

“Fluorocarbons” refer to a chemical substance group. The substances of said group include—if not absolutely exclusively—perfluorinated carbon chains.

A “permeability in such a manner that electrolytic processes are made possible” means in conjunction with the invention that the spacer is permeable at least to an electrolytic liquid.

By monofilaments of inert fluorocarbons being used as material for the spacer textile according to the invention, the spacer textile is continuously chemically resistant. Even if it comes into contact with aggressive chemical materials, it is fundamentally not attacked or damaged by said materials. As a result of the continuous chemical resistance, wear on the spacer textile according to the invention is only to be anticipated as a result of mechanical load.

The fibers preferably have electrical conductivity of less than 10̂-15 S/m at a temperature of 300 K. With corresponding conductivity, the spacer textile can also be used as an almost perfect insulator in electrical or electrochemical applications and methods.

It is preferred when the spacer textile has a weight per unit area of between 800 and 1765 g/m̂2. The compression strength of the spacer textile is preferably to be at least 10 kPa.

It is preferred when the fibers are of polytetrafluor ethylene (PTFE). A spacer textile of said material shows good mechanical damping properties along with good continuous chemical resistance—in particular even at temperatures of between 60° C. and 65° C. In addition, at a temperature of 300 K, it has electrical conductivity of approximately just 10̂-16 S/m.

It is preferred when the fibers of the spacer textile are round. Uniformity of the spacer textile is achieved as a result.

It is particularly preferred when the fibers are of 400 denier round ePTFE fiber, more preferred of GORE® RASTEX® ePTFE part no. 10642635. Said fibers are distinguished by the properties which are specified in an exemplary manner below:

Material: 100% extruded polytetrafluor ethylene with 400 denier nominal yarn count

No. of Test Parameter Unit Min. Max. samples method Yarn g/9.000 m 360 440 1 Weight count sample measuring per of a 45 m yarn long reel thread x 200 Tensile g/denier 3.0 N/A Average Strength strength of 5 testing samples device with 254 mm/min, GL: 269 mm Shrinkage % N/A 3.0 — DIN EN 14621; 15 minutes at 250° C.

GL: Gauge length, free clamping length of the yarn during the tensile test

The preferred material is an extruded fiber which is not matrix spun. It is, therefore, a so-called “solid wire”, the fiber preferably being particularly round and thick.

The spacer textile according to the invention can be produced in arbitrary geometrical forms, it being in a preferred manner a spacer knitted fabric or a spacer crocheted fabric. If the spacer textile is a spacer knitted fabric, it is preferred when the fibers of the spacer layer are knitted in cross-form. The fibers then form an X structure. It is further preferred when the fibers of the spacer layer are additionally knitted in the vertical form, in a so-called I structure. The X structure bestows stability on the surface structure between the top and bottom textile. The I structure is advantageous to the compressive strength.

In a preferred manner, the spacer textile has a thickness of between 1 mm and 4 mm, preferably of between 1.5 mm and 2.5 mm, more preferably of between 1.8 mm and 2.2 mm. As an alternative to this or in addition, the spacer textile is opaque, i.e. light cannot penetrate the spacer textile. Tests have shown that corresponding spacer textiles can be used in a versatile manner.

The spacer textile according to the invention can be used in an advantageous manner as a spacer for use in an electrochemical voltage cell with liquid electrolytes.

Corresponding electrochemical methods include, for example, the electroplating process or electrolytic refining. For example, in the case of electroplating, components are coated with metallic compounds by means of electrochemical deposition. Components to be electroplated from electrically conducting material or with an electrically conducting coating, in this case, are connected to a pole of a current source and are dipped into an electroplating bath. The electroplating bath is filled with an electrolytic liquid, into which another electrode, which is connected to the other pole of the current source, is also dipped. As a result of the current through the electroplating bath, metal from the electrolytic liquid is deposited on the component to be coated. If the component has a complicated form, the electrode is realized in a typical manner as a so-called manual electrode which is guided by a trained user around the component in such a way that a uniform coating is produced on all sides of the component. In the case of less complicated components, the electrode can also be arranged in a stationary manner in the electroplating bath and once again a uniform coating is produced on all sides. In this case, the electrode is referred to as a bath electrode.

Even when the above designs refer in particular to electroplating as an electrochemical process, they are applicable in general to all electrochemical processes which are carried out in an electrochemical voltage cell with liquid electrolytes.

In the case of all corresponding electrochemical methods, the electrode and the component or another electrode must be prevented from contacting each other and giving rise to contact arcing. In the case of a corresponding contact, a very high short-circuit current namely flows which damages both the electrodes and/or the component in an irreversible manner.

Through the use according to the invention of the spacer textile according to the invention as a spacer as at least in part sheathing of an electrode in an electrochemical voltage cell with liquid electrolyte, an effective protection is achieved both against contact arcing and against impact damage without the electrochemical process being fundamentally impaired. The spacer textile according to the invention is namely permeable to the electrolytic liquid and, as it is inert, also does not react with the ions contained in the electrolyte. It is consequently continuously chemically resistant. The method of the spacer textile in corresponding electrochemical processes can be further improved when the spacer textile is produced from fibers which insulate in an almost perfect manner. In practice, as a result, the spacer textile can only wear as a result of mechanical load. The frequency of maintenance intervals is clearly reduced in relation to a spacer of non chemically resistant material.

In addition, spacer textiles are distinguished in that they are able to dampen impacts as a result of their elastic deformability. The risk of component damage by, e.g. rubbing when the components are dipped into an electrochemical voltage cell, for example an electroplating bath, is consequently reduced. Mechanical protection is therefore achieved by means of the resilient damping produced by the spacer textile.

Over and above this, the spacer textile can be produced in arbitrary geometric forms such that an electrode is able to be totally surrounded by the spacer textile. In a preferred manner, the spacer can be realized in the form of a sheathing corresponding to the electrode. As there is then no free point present at which electrodes and/or components could contact each other, an effective protection against contact arcing, which results in irreversible damage to the electrodes and/or the component, is ensured.

Electrodes for electrochemical voltage cells are typically developed as flat sheets or are cylindrical in form. A spacer textile for a flat plate electrode can be developed as a double-coated spacer textile where the two layers are connected together in an essentially circumferential manner at their respective edge. The plate electrode can then be introduced between the two layers. If the spacer textile is to be used with a cylindrical electrode, the spacer textile is preferably in the form of a cylindrical coating. The coating can preferably have an inside diameter of 2 cm.

It is preferred when the electrochemical voltage cell with liquid electrolyte is an electroplating bath. The electrochemical process which is carried out in the voltage cell is then an electroplating process. For a cathodic electroplating process the anode is preferably sheathed and for an anodic electroplating process the cathode is preferably sheathed.

The spacer textile according to the invention is suitable in addition as a lining of operating, bearing and/or transporting surfaces. In this case, the spacer textile is designed as a mat on a corresponding surface in order to form a support for components in this way. The surface lined in this manner is distinguished by chemical resistance and damping action. In this way, components removed, for example, from an electroplating process can easily be placed on a surface lined with the spacer textile according to the invention without any residue of the electrolytic liquid from the electroplating bath possibly dripping from the component attacking the surface. Through the damping action of the spacer textile according to the invention, where applicable shocks occurring during transport on a surface, for example of a truck, are also kept at bay or are at least so strongly reduced that no damage occurs to the component. Damage during the placing of the components on corresponding surfaces can also be avoided as a result of the mechanical damping action.

It is possible to provide the side of the spacer textile according to the invention forming the surface of a lined operating, bearing and/or transport surface with a structure. Apart from the described damping action, protection against the unintended sliding of components on the surface is also achieved in this way.

The spacer textile according to the invention can be used additionally as filter or support material in chemically aggressive media. As a result of its inert properties, the spacer textile is not attacked by the chemically aggressive medium. The chemically aggressive medium, for example, can be sea water.

The use of the spacer textile according to the invention as sheathing of an electrode in an electroplating bath, as lining for operating, bearing and/or transport surfaces or as filter or support material is, where applicable, a separate inventive use. In the case of a corresponding use, where applicable it can be unimportant whether the fibers of the spacer textile are inert and/or of fluorocarbons.

The following spacer textiles have proven to be advantageous, in particular for use in electrochemical voltage cells, but also for other uses.

The first advantageous spacer textile is knitted from GORE® RASTEX® ePTFE part no. 10642635 on a double-ribbed Raschel machine with an electronic rib guide control unit made by Karl Mayer Textilmaschinenfabrik GmbH (Karl Mayer RD EL) with an E22 yarn count (i.e. 22 needles per 2.54 cm). The draw-in is provided with 50 threads per guide bar.

Fully drawn-in and with a distance between comb plates of 3.3 mm, with the control pattern

GB2 1-0-1-1/1-2-1-1//

GB3 0-1-0-1/0-1-1-0/0-1-1-0/2-1-2-1/2-1-2-1/2-1-2-1//

GB5 1-1-1-0/1-1-1-2//

a spacer textile is produced with a stitch density of 12 stitches per cm. Said spacer textile has a weight of 1,427.02 g/m̂2 and a thickness of 1.95 mm in the non-loaded state. The spacer textile produced in this manner is suitable, for example, for use in electrochemical voltage cells for the deposition of nickel on steel AlSi 4130.

From the identical material, using the same machine, fully drawn-in with the same control pattern and with an identical distance between comb plates, a second spacer textile is produced from GORE® RASTEX® ePTFE part no. 10642635 with a stitch density of 6 stitches per cm. The resulting spacer textile has a weight of 858.75 g/m̂2 and a thickness of 1.10 mm in the non-loaded state. The spacer textile produced in this manner is suitable, for example, for use in electrochemical voltage cells for the deposition of nickel on steel ST 13 and on tin.

The invention is now described as an example by way of exemplary embodiments with reference to the accompanying drawings, in which:

FIG. 1 shows a section through a spacer textile according to the invention; and

FIG. 2 shows an electroplating bath with a spacer textile according to the invention as a spacer;

FIG. 3 shows the spacer from FIG. 2;

FIG. 4 shows a truck with a spacer textile according to the invention as a liner of the transport surface.

FIG. 1 shows a cross section through a spacer textile 1 according to the invention.

The spacer textile 1 includes a top textile 2 and a bottom textile 3 which are connected together by support threads 4, 4′ as spacer layer 5. The top textile 2, bottom textile 3 and spacer layer 5 are formed by fibers. Said fibers are monofilaments of inert fluorocarbons, in the exemplary embodiment shown of polytetrafluor ethylene monofilaments (PTFE monofilaments).

The fibers are thick, round fibers. A good damping action is achieved by the thickness, whilst the roundness of the fibers results in a uniform spacer textile 1. 400 denier round ePTFE fibers or GORE® RASTEX® part no. 10642635 can be used as fibers.

In the exemplary embodiment shown, the spacer textile 1 is knitted, the support threads 4, 4′ of the spacer layer 5 being knitted both in the form of a cross (X structure; cf. support threads 4) and in a vertical form (I structure; cf. support threads 4′). The X structure bestows stability on the spacer textile 1 between the top 2 and bottom textile 3. The I structure is advantageous for the compression stability.

FIG. 2 shows an electroplating bath 11 filled with an electrolytic liquid 12 as an example of an electrochemical voltage cell with liquid electrolyte. An electrode 13 and a component 14 to be coated, both connected to a current source 15, are dipped into the liquid 12. The electrode 13, in this case, is connected to the positive pole of the current source 15, whilst the component 14 to be coated is connected to the negative pole of the current source 15. The electrode 13 consequently forms the anode and the component 14 to be coated forms the cathode for the electroplating process.

As a result of the current, which flows from the current source 15 via the electrode 13, the electrolytic bath 12, the component 14 back to the current source, metal ions from the electrolytic solution 12 are deposited on the component 14. As a result, the component 14 receives a coating 16 of the metal of the electrolytic solution. If the form of the component 14 is not very complicated, it can be sufficient for a uniform coating on all sides when the electrode 13 is realized in a stationary manner as a bath electrode. If the form of the component 14 is complicated, the electrode 13 is a manual electrode which is guided around the component 14 by a user in such a manner that a uniform coating is produced on all sides.

During the electroplating, in particular during the operation of dipping the component 14 to be coated into the electroplating bath 11 or removing it out of the electroplating bath 11, as well as—in the case of a manual electrode—when guiding the electrode 13 around the component 14, there is the risk of the electrode 13 and the component 14 contacting each other or at least coming so close that contact arcing is generated which damages the electrode 13 and/or the component 14 in an irreversible manner.

In order to avoid a corresponding contact between the electrode 13 and the component 14, a spacer 20 is provided according to the invention, such as is shown in more detail in FIG. 3.

The spacer 20 includes a spacer textile 1 and is realized as sheathing for the electrode 13. In the exemplary embodiment shown, the electrode 13 is shaped in the form of a cylinder. The spacer textile 1 is consequently knitted in the shape of a hose, one end of the hose being closed. The secure seat of the spacer 20 on the electrode 13 can be achieved by a corresponding fit. In the present example, the inside diameter of the spacer 20 is 2 cm whilst the electrode 13 has an outside diameter of 2.2 cm. However, it is also possible for particular fastening elements (not shown) to be provided for securing the spacer 20 on the electrode 13. Where the bath electrode 13 has another shape, the shape of the spacer 20 is able to be adapted in a corresponding manner.

The spacer textile 1 of the spacer 20 is produced from PTFE monofilaments. In this case, these are inert fibers which do not react with the electrolytic liquid 12 or the metal ions in the electroplating bath 11. The spacer textile 1 is therefore continuously chemically resistant, even at the temperatures of between 60° C. and 65° C. frequently present in the electroplating bath. In this case, however, at the same time it is also an almost perfect electric insulator and permeable to the electrolytic liquid 12 or the named metal ions such that the electroplating process is not impaired.

As a result of the spacer 20, it is impossible for the electrode 13 and the component 14 to be able to contact each other directly and for contact arcing to occur which would damage the electrode 13 and/or the component 14 in an irreversible manner.

At the same time, the spacer 20 is resiliently deformable as a result of the spacer textile 1 and can consequently dampen impacts in a resilient manner. This ensures that when a component 14 to be coated impacts against the electrode 13 sheathed by the spacer 20, the impact is absorbed in such a manner that no damage occurs to the component 14.

The spacer 20 according to the invention is distinguished therefore in that, without influencing the electroplating process, it provides continuously chemically resistant protection against contact arcing and damage to components 14 caused by impacts. As a result of the continuous chemical resistance, it is not necessary to change the spacer 20 in a regular manner.

FIG. 4 shows a further example of use for the spacer textile 1 according to the invention. The spacer textile 1, which is designed according to FIG. 1, in this case, is used as a lining of a transport surface 31. The transport surface 31 is situated on the top surface of a truck 30.

The spacer textile 1 is designed as a mat on the transport surface 31 and consequently forms a support for components (not shown) which are placed on the transport surface 31 and can then be transported by the truck 30.

The transport surface 31 lined in this manner is distinguished by chemical resistance and damping action. Thus, for example, components removed from an electroplating bath (cf. FIG. 2) can easily be placed on a transport surface 31 which is lined with the spacer textile 1 according to the invention without residue of the electrolytic liquid from the electroplating bath possibly dripping from the component attacking the transport surface 31. Through the damping action of the spacer textile 1 according to the invention, impacts arising, where applicable, on components lying during the transport on the transport surface 31, are kept at bay or at least are reduced so strongly that no damage occurs to the components. It is also possible by means of the mechanical damping action to avoid damage when the components are placed onto the transport surface 31.

The side of the spacer textile 1 which forms the surface of the transport surface 31 is profiled (indicated at 32), which provides a protective effect against the unintended sliding of components on the transport surface. 

1. Spacer textile (1) including a top textile (2), a bottom textile (3) and a spacer layer (5), wherein the top textile (2) and the bottom textile (3) are connected together by the spacer layer (5) in such a manner that they are at a spacing from each other, and wherein the top textile (2), bottom textile (3) and spacer layer (5) are formed by fibers, characterized in that the fibers are monofilaments of inert fluorocarbons.
 2. Spacer textile according to claim 1, characterized in that the fibers have electrical conductivity of less than 10̂-15 S/m at a temperature of 300 K.
 3. Spacer textile according to claim 1, characterized in that the fibers are of polytetrafluor ethylene (PTFE).
 4. Spacer textile according to claim 1, characterized in that the fibers are round.
 5. Spacer textile according to claim 1, characterized in that the fibers are of 400 denier round ePTFE fibers.
 6. Spacer textile according to claim 1, characterized in that the fibers are knitted in a cross-shaped manner and/or in a vertical manner (X structure, I structure, X and I structure).
 7. Spacer textile according to claim 1, characterized in that the spacer textile has a thickness of between 1 mm and 4 mm.
 8. Spacer textile according to claim 1, characterized in that the spacer textile is opaque.
 9. A method of using a spacer textile, comprising using a spacer textile (1) according to claim 1 for the at least in part sheathing of an electrode (13, 14) in an electrochemical voltage cell with liquid electrolyte (11), wherein the spacer textile (1) is permeable in such a manner that it enables electrolytic and electroplating processes.
 10. The method according to claim 9, characterized in that the spacer textile (1) is used for a manual electrode.
 11. The method according to claim 9, characterized in that the spacer textile (1) is realized in the form of a sheathing (20) corresponding to an electrode (13).
 12. The method according to claim 9, characterized in that the spacer textile (1) is realized in the form of a cylindrical coating.
 13. The method according to claim 9, characterized in that the electrochemical voltage cell is an electroplating bath.
 14. The method according to claim 9, characterized in that in a cathodic electroplating process the anode is sheathed and in an anodic electroplating process the cathode is sheathed.
 15. A method of using a spacer textile, comprising using a spacer textile (1) according to claim 1 as a lining of operating, bearing and/or transport surfaces (31).
 16. The method according to claim 15, characterized in that the spacer textile (1) has a profiled surface (32).
 17. A method of using a spacer textile, comprising using of a spacer textile (1) according to claim 1 as filter material in chemically aggressive media.
 18. A method of using a spacer textile, comprising using a spacer textile (1) according to claim 1 as support material in chemically aggressive media.
 19. The method according to either of claim 17 or 18, characterized in that the chemically aggressive medium is sea water.
 20. Spacer textile according to claim 5, characterized in that the fibers are of GORE® RASTEX® Part No.
 10642635. 21. Spacer textile according to claim 7, characterized in that the spacer textile has a thickness of between 1.5 mm and 2.5 mm.
 22. Spacer textile according to claim 21, characterized in that the spacer textile has a thickness of between 1.8 mm and 2.2 mm.
 23. The method of claim 12, characterized in that the cylindrical coating has an inside diameter of 2 cm. 